RIE fabrication method of ARS for plastic lens

Generally, an optical lens is reduced its reflection by multilayer anti-reflection coating. However, there are some problems, for example, those coatings cannot be attached for some kind of resins, and show clack or peeling by temperature change or humidity. Lately, anti-reflection effect by sub-wavelength structure on optical lens surface is studied widely. This is called ARS, Anti-Reflective Structure. ARS solved above problems, and has low dependence on incident angle of light. Conventionally, for mass production of ARS lens, we tried injection molding. That is, fabricating fine structure on mold core, and transfer the structure to plastic resin. However, the transferring is very difficult, because of its fineness and adhesion resin to the core. Besides, mold for high transcription is expensive. We tried to fabricate ARS on plastic lens surface by Reactive Ion Etching. Controlling plasma condition at each etching process cleverly, we successfully obtained fine ARS on optical lens surface. The structure has high aspect and narrow pitch which is about 0.1μm, and show good anti-reflective property.